Biochemical markers of vasospastic coronary artery disease

The risk factors for vasospastic angina pectoris (VSA) have not yet been well defined. We compared the plasma levels of lipids, apo(lipo)proteins, remnants of triglyceride (TG)-rich lipoproteins, oxidized low density lipoprotein (Ox-LDL), cholesteryl ester transfer protein (CETP) [which transfers esterified cholesterol (EC) from HDL to TG-rich lipoproteins and reduces plasma HDL levels], high-sensitivity C-reactive protein (hs-CRP), homocysteine and plasminogen-activator inhibitor (PAI)-1 in background-matched groups of controls, and patients with VSA or coronary atherosclerotic disease (CAD) (n=50 subjects each).

The cholesterol levels of remnant-like particles (RLP), which are equivalent to the remnants of TG-rich lipoproteins, were measured using a precipitation method. Ox-LDL, CETP and PAI-1 were measured by means of sandwich ELISA; hs-CRP by means of nephelometry; and homocysteine by means of HPLC. Plasma LDL-C levels were high only in the CAD group, and plasma apo E and PAI-1 levels were high only in the VSA group. The plasma levels of TG, apo CII and RLP-C were highest in the VSA group, followed by the CAD group. The plasma levels of apoB, apo CIII, Ox-LDL, CETP, hs-CRP and homocysteine were equally increased in both the VSA and CAD groups. The increases in plasma RLP-C, CETP, hs-CRP and homocysteine were not significantly different between stable and unstable states of angina pectoris in either the VSA or CAD group.

The increases in plasma TG-rich lipoproteins and their remnants were more significant markers of VSA than of CAD. The increases in plasma CETP, Ox-LDL, hs-CRP and homocysteine were equally important markers of VAS and CAD.